1. Field of the Invention
The invention relates in general to an active matrix organic light emitting diode (AMOLED) panel, and more particularly to an AMOLED panel driven by a large current.
2. Description of the Related Art
In an active matrix organic light emitting diode (AMOLED) display, a number of pixels in an AMOLED panel display an image to be represented generally. The pixels are controlled to emit the luminance required according to a data signal.
FIG. 1 (Prior Art) is a circuit diagram showing a conventional AMOLED panel 10. In the AMOLED panel 10 and in a writing timing stage, a scan signal Scan outputted from a scan driving unit 14 turns on a transistor T1 and a transistor T2 in an AMOLED pixel unit 11. A transistor T3 also generates a current IData according to the current IData possessed by a data driving unit 12. Because the transistor T3 and a transistor T4 form a current mirror circuit structure, the transistor T4 generates a current IOLED in proportional to the current Idata. The current IOLED is outputted to a light emitting diode 16 to make the light emitting diode 16 emit the corresponding luminance. Meanwhile, a capacitor C is also charged to a corresponding voltage level.
Then, in a displaying timing stage, the scan signal Scan turns off the transistor T1 and the transistor T2, so the transistor T4 is electrically isolated from the data driving unit 12. A voltage difference between a source and a gate of the transistor T4 is stably kept at the corresponding voltage level through the capacitor C, and the current IOLED is also stably kept at a predetermined value. However, the magnitude of the current IData, which is driven by the data driving unit 12, is limited, and the area of the data driving unit 12 has to be enlarged if the larger driving current has to be provided. Consequently, the cost is increased.